Efforts are being deployed to create different means to aggregate resources from different eNBs (e.g. R12 LTE inter-eNB aggregation using dual connectivity). The objective is typically to enable means for an operator to offload some traffic from a macro cell/eNB to another cell/eNB which cell may possibly offer some form of hot spot overlay network, or to enable higher throughput.
A WTRU may be configured for dual connectivity. Dual connectivity may be configured by the network either for throughput benefits (mainly for the downlink) or for offload purposes (relieving an eNB deployed for macro coverage from user plane traffic towards another eNB deployed for capacity enhancements). When a WTRU is configured for operation with dual connectivity, it may use radio resources associated to different eNBs where the interface corresponding to each set of resources is herein referred to as a Uu interface. Each Uu interface may itself be configured with one or a plurality of serving cells in case intra-eNB carrier aggregation is also supported. The WTRU may then be scheduled for any type of data by a Macro eNB (MeNB) which eNB controls the RRC connection, as well as by a Secondary eNB (SeNB) which may be used for exchanging user plane data. This form of dual connectivity may also be referred to as Inter-eNB Carrier Aggregation (inter-eNB CA). In this case, the WTRU may be configured with different MAC entities, one for each configured Uu interface.
Some prioritization and power scaling mechanisms have been specified for intra-eNB CA, however these mechanisms involve minimal if any coordination between schedulers, and control plane data is only transmitted using a single Uu interface.